Method of and apparatus for the generation of sounds



Feb, 2S, 1928., I 1,661,058

L. s. THEREMIN METHOD OF AND APPARATUS FOR THE GENERATION OF SOUNDS Filed Dec. 5, 1925 6 Sheets-Sheet l fi Jae/ways Feb, 28, 1928. 1,661,058

L; $.THEREMHN METHOD OF AND APPARATUS FOR THE GENERATION 0F SOUNDS Filed Dec. 5, 1925 s Sheets-Sheet 2 Feb 28, 1928, 3,861,058

L, s. THEREMIN METHOD OF AND APPARATUS FOR THE GENERATION 0F SOUNDS Filed Dec; 5, 1925 e sheets-sheet :5

FQB, 28 1928.

L. s. THEREMEN METHOD OF AND APPARATUS FOR THE GENERATION OF SOUNDS Fl ed Dec 5 1925 L. S. THEREMIN METHOD OF AND APPARATUS FOR THE GENERATION 0F SOUNDS 6 Sheets-Sheet 5 Filed Dec. 5. 1925 rig - Jnvenzar 1 fin Nu, Mm A VAVI 15 Feb. 28, 1928. L.- 5.THEREM|N METHOD OF AND APPARATUS FOR THE GENERATION 0F sounps Filed bee. 5, 1925 6 Sheets-Sheet Patented Feb. 28, I923;

LEO ssnnenmwlrscn THEBEMIN, or Lamncm, auasu, assmnon To an rm or u. .1. commune um; somm, a. m. n. 11., or nannm, enamm.

METHOD .0! AND APPARATUS FOR THE GENERATION 01' SOUNDS.

Application filed December 5, 1925, Serial No. 73,529, and in Germany December 8, i824.

This-invention relates tosound enerating a paratus or instruments of t e type embo ying an electrical vibrating system. It aims to provide a novel method of and means for producing sounds in musical tones or notes of variable pitch, volume and timbre in realistic imitation of the human voice and various ,known musical instruments. One object of the invention is to provide a simple and inexpensive instrument capable of producing musical tones according to the method embodyin the same, the pitch, volume and timbre 0 which sounds may be varied over a wide range, and with delicate graduations.

'An instrument embodying the invention comprises a sound reproducer, such as a telephone receiver or loud-speaker connected to an oscillating system adapted to be controlled or ailected by an object or objects, such as the hands or fingers of an operator held in relative position in proximity to an element of the system. For example, an electrical oscillating system including oscillator tubes of the electro-ionic type may be employed, and the circuits of the system may be so correlated that the frequency or frequencies of the electrical oscillations will vary in accordance with the variations in the electrical capacity or other characteristic of the controlling circuit caused by the movements of external objects, such as an operators hand or fingers as above stated.

The operators hands, or the objects moved by him are not required to make physical contact with the instrument, but if the instrument is arranged to permit such contact, the generation or production and control of the sound is not elfected directly thereby as is the case with the ordinary musical instruments.

In order to generate clear sound or musical tones and permit ready control thereof, a plurality of oscillators are employed, having a frequency above the audible range but interacting with each other to produce interference 01' beat-notes of audible frequency. The frequency of one or more of the oscillators is controllable by the operator to produce beat-notes of the desired pitch. The apparatus in preferred form also embodies means for controlling the volume and timbre of the music.

characteristics of the sound or music pro duced thereby may be changed as desired in mutation of various other instruments, whereas the ordinary musical instrument, such as the violin, produces sound tones of fixed and well-known characteristics. The instrument is not limited, however, to the productlon of music but may be employed to generate sounds or operate signals for various purposes. i

Other objects and advantages of the in ventlon, particularly with reference to electrical elements and circuits and their arrangements in systems for securing various results in different constructional embodiments which have been devised, will appear from the following description considered in connection with the' accompanying drawings in which are shown several modified forms of the'invention. Various practical embodiments of the invention are hereinafter described in order tomake a full and complete disclosure, but the invention obviously is not limited to the specific arrangements shown and it is to be understood that no limitations thereon are intended beyond those set forth in the appended claims.

Referring to the drawings Fig. 1 is a. diagrammatic v1ew of electrical circuits and apparatus arranged in accordance with the invention for the production 01 a single tone of variable pitch;

Fig. 1 is a similar viewof a modification;

Fig. 2 is a similar view of a further modification embodying amplifiers;

Fig. 3 is a diagrammatic view of a modified form of reproducer circuit;

Figs. 4 and 5 are diagrammatic/"views of different forms of control circuits;

Fig, 6 is a diagrammatic view of a system for producing two tones;

Figs. 7 and 8 are similar views of systems for producing four tones;

Fl 9 to M illustrate means for regulatt e volume of the sounds;

.i s. to 18 illustrate systems for sw1tehing t e tone on and ed by means of a wire connection;

llfig. 19 shows a systemfor eectlng the same result by a modified form of control;

l i "s. 20 to 22 show systems for eliminatin. t e natural oscillations;

figs. 23 to 26 illustrate systems for re ulating the timbre of the sound or tone; an

Fig. 27 illustrates a complete system for simultaneously producing a plurality of sound or musical tones on the same or different pitches, and embodying means for controlling the characteristics thereof.

ftl

till

A referred form of instrument embodying the invention and operable according to the method embodying the same, comprises the following elements: k

T. A control element or electrode with relation to which an object such as the hands -or fingers of an o erator are moved to control the pitch an character of the sound tones emitted by the instrument. daid ele- 1 ment does nbt function like the antenna in a wireless receiver set or apparatus, i. e., it does not receive or detect radiantenergy transmitted from a distant transmlttmg station, but has a novel and radically different function as will appear from the detailed description in connection with the var1ous circuit arrangements illustrated in the drawllll. Uscillating circuits adapted to produce one or more beat-notes of audible fre quency.

lllll. cans for regulating the volume of the'sound tones.

TV, Means for switching individual sound tones on and off as desired.

V. Means for controlling the timbre of the sound tones.

VT. Means for eliminatin or nullifying the natural oscillations of t e amplifier or reproducer to prevent the production of undesirable noises or distortion of the sound tones.

lin broad aspect, the means of the invention comprises an oscillating system capable of producing audible sound tones and adapted to be influenced or affected by an object or objects, such as the hands or fingers of an operator moved in proximitive relation to an element thereof, together with a sound reproducer operatively connected to said system. Stated differently, the invention embodies a method and means for producing sound or musical tones characterized by an oscillating system in which the period is varied and the characteristical sound emission from which is changed by the movement of an object or objects in proximitive relation to an element thereof. The said system may be electrical and so arranged that movechange the c ectrical characteristic thereof such as the electrostatic capacity between certainelements which determine the period of the oscillator; but while such a system is disclosed and hereinafter described in detail, it is obvious that other types of oscillating systems and other means of control may be em loyed to accomplish the same result.

n Fig. 1 of the accompanying drawin 's a system is shown embodyin an electrode or control-element l operativel y connected to an electrical oscillating system and an electrical sound-reproducer. The electrode or control-element is in this instance connected to an oscill: tor 2 of the electro-ionic type and to a reso ant circuit 3 which is traversed by an oscillatory current, the frequency of which depends upon the constants of the circuit and of the circuits conductively or inductively related thereto. The oscillator 2 is represented as of the filamentary-cathode type operating by an electron discharge from the cathode, but other forms of oscillators may be used and are intended to be included by the phrase electro-ionic.

A second oscillator 4t is shown connected ment of an operators hands or fingers will to the circuit 3, said last mentioned oscillator with the oscillator 2 being arranged to control a third electro-ionic tube 5 through coils 6 and 7 which are inductively related to the two oscillators. it condenser 8 is represented as interposed between the coils 6 and 7 and the tube 5, and a grid-leak resistance 9 is shown connected between the grid terminal of said condenser and the cathode circuit. The output circuit of the tube 5 is connected through the audio transformer 10 to a tone reproducer or loudspeaker 11. The tubes 2, t and 5 are connected to a suitable source of current, such as a battery, as indicated at 12.

The oscillating frequencies of the oscillators 2 and 4 are preferably above the range of audibility; but are nearly the same so that the interference frequency produced in the circuit of the tube 5 will be relatively low and produce a beat-note of audible pitch in the loud-speaker ll. The frequencies of vibrations inthe circuit of the tube 5 may be called audible frequencies as they will have substantially the same number of vibrations as the vibrations of an audible sound Wave. The pitch of this note, and the presence and strength of the overtones are controlled by selection and arrangement of the condensers, inductances and other elements of the cir cuits in a known'manner.

The frequencies of the oscillators 2 and 4 may be of the order of 500,000 cycles per secend, the precise frequency being so chosen that no interference with radio broadcast reception is produced. The values of inductance and capacity employed in the oscillattill well-khmvn principles to provide the desired frequencies and the variation of the ca acity of the variable oscillator is efi'ecte by the change of capacity of the controleleelrode, which change in capacity in instruments that have been built is of the order of micro-farads. It will be understood that this change of capacity effected by external control is so correlated With the capacity in the oscillator circuit that the resultant range of pitch of the musical instrument covers several octaves.

The sound generated in and emitted through the loud-speaker is also controlled by the movement of an object or ob ects,

' such as an operatofisfingcrs in proximitive relation to the electrode or control-element 1 which is connected to the oscillating circuit 3 and to the grid of the oscillator 2. The electrical characteristics of said control element influence the periodor frequency of the oscillator 2 and the characterof the beatnote in the reproducer. As the operators lingers are moved in suitable relatlonship with said control element, the pitch of the beat-note in the reproducer ll-is varied, and continuous variations may be produced with most delicate graduations by the continuous movement of the fingers- This control is primarily the result of changes occurring in the electrostatic capacity between the control element and the ground potential or between the control element and other elements of the circuits. Therefore, it is obvious that other objects than'the operators fingers would be operable to vary the tone produced. Furthermore, it will be appreciated that the amount and direction of the controlling movement will depend somewhat upon the dimensions and arrangement of the control element which may be of such character that movement of the fingers to the extent required to play any F ordinary instrument such as the violin, will produce a corresponding effect and note change in the present sound generating instrument, so that one who has learned to play the violin or some other instrument will have little difficulty in playing the present instrument.

The system shown in Fig. 1 isv similar to that shown in Fig. 1, except that couplin condensers l3 and 14: are substituted for the inductive couplingbetw'een the circuits of the latter. A great many other modifications of this kind may be made in'the arrangement of the electrical oscillating system without departing from the scope of the invention.

In Fig. 2 a further modification including amplifiers is shown. Amplification of the electrical currents may be eliected in various ways, but it is preferable to use an arrangement in which there is a minimum distortion of the sound tones. It is also genertube 19.

ally preferable to amplify each of the highfrequenc currents separately, rather than the'low-frequency beat-note, although a lowfrequency ampli or may also be utilized.

. Referring to Fig. 2, an electrode or control-element 15 is shown connected to an oscillator-16, the output circuit of which is connected to an amplifier 17, preferably of the clectro-ionic type'as represented. A second or auxiliary oscillator 18 is shown connected to a second amplifier 19. The output circuits of said amplifiers 17 and 19 are connected to the input electrode or grid of an elcctro-ionic tube 20, whereby a beat-note of aud'ble frequency is produced in the output circuit thereof. The output circuit of the tube 20 is connected through a transformer 21 and throu h an audio-frequency amplifier 22 to a loud hpeaker 23. An anode battery 25 is connected in parallel to all of the electro-ionic tubes in the usual manner. A noninductive resistance 24 is connected between the grid and cathode of the tube 20 and a condenser 26 is connected between the grid of tube 20 and the "node of the amplifier A second condenser 27 is connected between the condenser 26 and the battery 25. This condenser is preferably variable as indicated. Condensers 28 and 29 corresponding with the condensers 26 and 27 are also provided in connection with the amplifier 17. In the arrangement just described, the high-frequency oscillations of the controllable oscillator 16 and the auxiliary oscillator 18 are amplified separately, and then the combined oscillations are amplified together. In Fig. 3, a further modification of the amplifier is shown. The left hand portion of Fig. 3 is the same as Fig. 2 as far as the line III-III. The amplifier 22 is shown connected. with the transformer 21 to which are connected four amplifiers 31, 32, 33 and 34, the latter being inductively connected with the amplifier 22 through the transformer 30. In this instance, amplifiers 32, 33, and 34 are connected in parallel to obtain a direct-current intensification, and said three amplifiers are connected in group to the fourth amplifier 31. The tone reproducer 23 and the anode battery 25 are connected as in Fig. 2. This arrangement is suitable especially by reason of its high elliciency for comparatively particularly for bass tones.

The oscillations of the controllable oscillator and the fixed oscillator are made independent of each other, and for such reason the amplification of each current takes place separately. Each oscillation is thus first amplified individually, and then only is amplification of the combined oscillations of feeted.

The connection of the control-element to the oscillating system may be modified variously While still obtaining the desired re:

low frequencies,

sult. A plurality cl electrodes may be employed to produce a plurallty of sound tones simultaneously from the same objectmoved tin-relation thereto. F m

nearer to one conductor than the other, the

pitch or one tone will increase while that of the other will decrease. Three or more conductors maybe provided, preferably in symmetrical arrangement, or a plurality of symmetrical groups of conductors may be arranged and controlled by different objects or fingers of the operators hand.

Connection of the conductor or conductors to the oscillator should be such that the changes in capacity will produce a considerable change in the oscillator. Connection may be made either to the grid or anode circuit of the oscillator, the most suitable connect-ions being illustrated in the drawings.

ln Fig. 4 a connection of the control element to the anode circuit is shown. With the controllable oscillator 7 3 is associated an oscillating circuit including inductances 7d and and condensers 76 and 77. Energy is supplied to the oscillator by an anode battery indicated diagrammatically at 78. The control element 79 may be connected with the plate circuit as shown in full lines at 79, or with the grid circuit as shown in dotted lines at 79. lt makes little difference whether the control element is connected the one way or the other provided conditions are otherwise equal. But if this is not the case, the control element is connected prelerably to the larger inductance. The sensitiveness of the s stem may be increased by grounding the circuit at 80, but as a rule this connection is not required in view of the large counterpoises of the oscillating c-ircuit.

lln the system illustrated in Fig. 5, the.

control element 81 is inductively cou led with the oscillator 83 through the me ium of a coil 82. An adjustable condenser 84 is shown arranged in the oscillating circuit of the oscillator 83 by which the control circuit is tuned. lln this system, by reason of the coupling coil 82, the control element may be at a somewhat greater distance from the oscillator 83.

lln order to produce a plurality of sound or musical tones simultaneously, a pluralit of interfering oscillators may be employe For instance, three oscillators properly arranged will produce two tones, one resulting from interference between the first and second oscillators and the other resulting from interference between the second and neonate third oscillators. In like manner, three tones may be produced by tour oscillators and so on.

lln Fi 6is represented an arrangement for pro ucing two sound tones simultaneously by the use out three oscillators, each tone being separately controllable. 01cc control electrode 35 is shown associated with an oscillator 36 and with a low-frequency detector tube 37. Another control electrode 38 is shown associated with an oscillator 39 and a low frequency detector tube l6. The said detectors 37 and'dO are both 'responsiiie to thcfined oscillator a l. An amplifier 42 responsive to both of the beat-notes or'tones is shown connected tlirough a transformer 43 with a dound reproducer 44.

Fig. 7 illustrates a tr rther modification comprising four control electrodes, viz d5, 45, 45 and 45' respectively associated with oscillators l6, d7, 48 and d9, whereby four tonesmay be produced simultaneously. The four oscillators coo crate with a fixed oscillator 50 and are in actively connected with detectors 56, 57, 58 and 59 through coils 51, 52, 58, and 5t. Each is also con nected with one of the coils 60, 6t, 62 and 63 of a transformer. tlondensers 6t, 65, 66 and 67 are connected in parallel with said coils 60, 61, 62 and 63. The neutral points of all four coils are co nected with the coupling coil 55 of a fixed oscillator 50. A secondar coil 68 of the transformer is con till lid

necte to the amplifier 69 which operates the from which the combined tones are t-ransmitted to the reproducer 71. through the transformer 70.

The detectors used in connection with the above systems may be of any suitable type, crystal detectors being considered generally preferable.

lFor regulating the volume of the sound, the intensity of the current may be varied and variation of the current intensity may be effected in several ways.

Referring now to Fig. 9, a connection is shown in which the oscillator or amplifier 85 which generates the sound tones actuates the reproducer 86, to which an adjustable resistance 87 is connected in parallel. The resistance 87 is adjusted by means of a pedal or the like, and controls the volume of the sound. The adjustable resistance 87 may lid also be connected in series with the reproducer.

Fig. 10 shows a further modification in which an adjustable resistance 88 for controlling the volume, varies the cathode current of the amplifier 89, which in turn controls the reproducer 90. I

The system illustrated by the dlagram of Fig. 11 is similar to that shown 1n F1 10, except that the cathode current is regu ate d inductively fronrthe high-frequency circu t of the tube 100 iii the amplifier, with utilization of a greater or lesser energy absorp tion in the conductor 92 as determined by its resonance with the oscillating circuit 91 variable according to the operators movement of his fingers or other object with relation to the conductor.

The conductor 92 is connected with a coupling coiL 93 which latter is inductively related to a coupling coil 94 connected in series with the coupling coil 95 for the oscillating circuit 91, and a coupling coil 96 for the cathode of the direct-current amplifier. Both coupling coils 94 and 95 cooperate so that maximum energy will be generated when the control circuit and oscillator circuits are in resonance.

The conductor 92 is a separate control element for regulating the sound volume and will be referred to as the sound-volume control element or electrode. Adjustment may be so efi'ected that resonance occurs when the controlling object is either nearest to, or altogether removed from this electrode. Therefore. while one hand of the operalor generates the various sound tones in the first or sound generating electrode, his other hand may regulate the intensity of thm tone at the second or sound volume electrode.

The system in Fig. 11 is intended to be connected with the left-hand end of the diagram of Fig. 2, the line TIT-III in Fig. 11 indicating its point of connection with Fig. 2. The amplifier 98 which is also a directeurrent amplifier controls the reproducer 99.

The system shown by the diagrams of Figs. 12. 13 and 1 1 are similar to that shown in Fig. 11.

In Fig. 12', the cathode current for the amplifier 97 is generated by direct connection of the transformer 96 with the oscillating circuit 91.

In Fig. 13, the resonance transmission of energy to the circuit 102 through the circuit 101 is utilized under the influence of the controlling object or its distance from the sound volume control electrode.

The sound volume control electrode 92 is directly connected to the anode or the circuit 101 of the oscillator 100. and the circuit 102 which is coupled therewith supplies current to the cathode of the amplifier 97 over the variable transformer 103.

controlling the current serving for In Fig. 14, the sound volume is regulated by varying the average grid otential in one of the amplifiers by means 0 the non-inductive resistance 104, which is also in the anode circuit of the oscillator 98. The circuit of the sound volume electrode 92 is coupled with the oscillatin circuit of the tube 100,

which is connected with the non-inductive resistance 104. If a finger or otherobject is made to approach the electrode 92 the The diagrams of Figs. 9 and Marc mostefficient under normal conditions.

The preferred means for switching the sound tones on and oil comprise means for producing tones in the reproducer.

Fig. 15 shows an ordinary switch 105 in the plate circuit of the amplifier in series with the reproducer 106 as shown in full lines, or in parallel as shown at 105 in dotted lines.

As shown in Fig. 16, the primary winding of a transformer 10? may be connected in the plate circuit of the amplifier and the tone producer 108 and the switch 109 connected in the secondary circuit of the transformer. This eliminates the undesirable constant component of the pulsating current through the reproducer.

The diagram of Fig. 17 is similar to that of Fig. 16, but the transformer 107 is re placed by a choke coil 110 from which a circuit is branched in parallel, the reproducer 111, the switch 112 and the condenser 113 being connected in series in thiscircuit.

In Figs. 18 and 18, the switch is in the cathode circuit. In Fig. 18 the switch 114 controls the current from the filament battery 115 of an amplifier 116, in the plate circuit of which the reproducer 117 is arranged. In Fig. 18", the switch 119 is in a shunt circuit 118 of the cathode heating circuit which is connected with the filament battery, said battery being in continuous connection with the filament Wire in series with a resistance 121.

In Fig. 19 is illustrated an arrangement for switching the tone on and off by a con-v trol analogous to the arrangements for varying the volume of sound shown in Figs. 11 to 14.

The system of Fig. 19 is intended to be connected with the system of Fig. 2 along the line III-III as in the arrangement of Fig. 11. The two direct-current amplifiers 97 and 98 control the re-producer 99. A third control element 122 is provided for switching the tones on and off through the medium of the cathode current, and in whereby a corresponding voltage llll lid

operated like the sound-generating and sound volume electrodes. The control element 122 is coupled with a control circuit by a coil 123, which circuit includes coupling coils 124, 125, and 126. The COll 125 is coupled with the amplifier corresponding with the tube 160 in Fig. 11 and the coil 126 is con ledwith the cathode current of the amplifier 127. Current from the anode battery 129 flows through a relay 128 which 0perates a switch 130. The switch controls the circuit of the cathode battery 131 for the heater of the direct-current amplifier 97. By the operators movement of his hand or other object with relation to the electrode.

122, the filament current of the amplifier 97 and consequently the tone, is cut on or oil.

The systems of Figs. 16' and 17 are considered superior to that of Fig. 15, while the systems of Figs. 18 and 19 are regarded as preferable because the switching on and off will take place without any noticeable interval.

Fllimination or neutralization of the various natural oscillations in the apparatus is desirable to improve the qualit of the sound or musical tone and may be e ected through compensation by means of an electric sys-v tem of the same frequency and damping as is possessed by the oscillating system, the action of which is to be paralyzed.

Tn Fig. 20 is shown a reproducer 132 to which is connected a circuit with corresponding oscillation constants. This circuit comprises the inductance 133, the non inductive resistance 134 and the condenser 135, which are connected in series and are variable. The resistance and the inductance in particular, are preferably variable individually.

its represented in dotted lines in Fig. 20,

the arrangement may also be such that the circuit of these oscillation constants, comprising the inductance 133', the condenser 135 and the non-inductive resistance 134, is connected in parallel with the reproducer 132.

Should natural oscillations of various parts exist, for example, if the horn of the loud-speaker possesses a natural oscillation and the diaphragm of the loud-speaker possesses another natural oscillation, a com pensating oscillating circuit of the same period is employed for each natural oscillation, the circuits being connected either in series or in parallel.

Fig. 21 shows such a series connection. Three oscillating circuits 137, 138, 139, each or? which comprises an inductance, a noninductive resistance and a condenser, are shown connected to the reproducer 136.

According to Fig. 22 the arrangement may be such that parallel to the reproducer 149 are connected the oscillating circuits 141, 142, M3, each consisting of an inductance, a

'plifiers for example.

ca acitance and a non-inductive resistance.

These means for eliminating the natural oscillations may find general applicationbcyond the example statedabove, for instance in sound amplifiers of any kind or their equivalents.

The variationof the quantitive composition of the over-tones in the sound or m ;ical tones may be effected by various deformations of the primary alternating current, by utilizing the curved parts of the amplifier characteristics.

The composition of the overtones may also be varied by increasing or reducing the overtonesof the higher order by inserting oscillating elements comprising'capacitances and inductances of suitable values.

Fig. 23 illustrates such a system of connections. The oscillator or amplifier 144 supplies the transformer 145, the secondary winding of which controls the reproducer 146. A variable inductance 147 with a corre'spondingly variable capacitance 148 are connected in parallel with the reproducer. If the inductance alone is used, the overtone frequencies pass through the reproducer. 1f the capacitance alone is used, the overtone frequencies pass throu h the condensers and do not affect the repror ucer. Tit both the inductance and capacitance are used together, the correct composition of the overtones is obtained. llnstead of the arrangement described, a variable choke coil 149 and a variable condenser 150 may be connected in series with the reproducer 146 as indicated in dotted lines. 111 this case, the connection 151 is eliminated. lBoth arrangements may be provided together, but the connection 151 is eliminated in this case also.

Fig. 24 illustrates a simple expedient tor varymg the characteristic of one of the am- The plate potential of the amplifier 152 for the reproducer 153 may be varied by the adjustable resistance 154. The cathode current may be varied by the rheostat 155, or the grid potential by the rheostat 156. The connection to the other parts of the system as shown in Fig. 2 is effected by the transformer 21.

lln the selection of such characteristics as are required for the given'proportion of overtones, perfect results may be obtained by the combination of the characteristics of various electro-ionic tubes, for instance by the parallel connection of tubes with different operating characteristics.

Tn the diagram of Fig. 25, the transformer 21 which may be connected to the system of Fig. 2, controls the grids of four amplifiers 157, 158, 159 and 160. From each plate of said amplifiers, current flows to the reproducer and the anode battery 166 through rheostats 161, 162 and 164, one for each amplifier. One ofthe rheostats 167, 168, 169 and 170 is arranged in the filament circuit of each amplifier. These 'i'esistances correspond to the resistances 154 or 155, of Fig. 24. However, the'corresponding resistance 156 is eliminated in this system. The system of Fig. 25 affords more delicate graduations than that of Fig. 24.

The ,timbre is regulated in the above cases by varying the characteristics of the tubes by suitably adjusting the resistances.

1 Fig. 26 illustrates a system of connections for varying the timbre by varying the magnetic induction of the transformer core connected in the plate circuit of one of the amplifiers. The primary winding 171 of a llflllSfOlIl'K-l' 172 is connected in the plate circuit of an amplifier. A secondary winding 17 3 is connected to the reproducer 174. The transformer is furthermore provided with a third winding 175, the energization of which is varied by the rheostat 176. By adjusting the rheostat. 176, the magnetization of the core 17 2 is changed, which causes a variation of the timbre in the reproduce! 174-. This system is simpler than that according to l ig. 25, but does not give such gradual adjustment.

Fig. 27 is a diagram of a complete instrument for two tones. The system comprises two sound generating control elements 177 and 184, for the first and second tones respectively, and a sound volume control element 207.

The sound generating control element 177 for the first tone is connected with the circuit 179 of an oscillator 178 and the circuit is grounded. A detector 180 is included in the first system and a detector 187 is included in the second system. Said detectors are connected by a coupling coil 181 and a condenser 182. A non-inductive resistance 183 is inserted between the grid and the filament of the detector 180 for the purpose of maintaining the grid of said detector substantially at the initial potential.

The sound generating control element 184 of the second system is similarly connected with an oscillator 185 and a circuit 180, the condenser 189, and the resistance 190.

The two detectors 180 and 187 transmit the low-frequency oscillations to the amplifier 193 by means of the transformers 191 and 192. The fixed oscillator 194 is connected to the calibrated oscillating system 195 in a corresponding manner and is also connected with the two tone systems or their first amplifier 193. The latter may then control the amplifier systems 197, 198, 199, 200 by means of the transformer 196 for the purpose of producing a better effect. These am plifiers are controlled by the rhcostats 201, 202 and 203 in the plate circuit and by rheostats 204-, 205, 206 in the filament circuit.

The sound volume control element 207 controls through the absorption system 208,

transformer 211.

The resistances 201, 202, 203, 204, 205,

and 206 serve for producing different kinds of tones. The rheoslat 220 permits a regulation. of the filament current for all tubes. The condenser 221 serves for the regulation of the timbre in the reproduccr 213, while the choke 222 exerts a similar etlect upon the reproducer 214. If it is desired to dispense with the sound volume controlelement 207, the rheostat 2233 indicated in dotted lines should be connected in circuit.

It will be readily understood that the systems of cormectiou illustratml and described are only a few examples of how the invention may be enlarged upon. As a matter of course, it is possible to vary the individual systems in many ways according to developments made in the wireless industry.

By a phase displacement of the individual sound reproducing systems, an apparent wandering of the sound tones in space may be produced. The invention may if desired be used in conjunction with a broadcasting transmitter, whereby the frequency variation caused by the approach of a body towards the control element of the oscillating system will directly influence the broadcasting transmitter so that the electric oscillations corresponding with the sound oscillations are amplified and directly transmitted. in playing on this instrument, the microphone or microphones and the distortions caused thereby are eliminated, so that a clearer reproduction is assured.

1 claim:

1. A tone generating system controlled by the hand and comprising an electrical circuit embodying an oscillation generator,

'mcans in said circuit including a conductor having a field which when influenced by a hand moving therein will vary the resonant frequency of said circuit according to the movement of said hand only, and a sound reproducer connected with said circuit for emitting tones according to the electrical variations occurring in the circuit.

2. A tone generating system controllable by an object moving relative thereto, comprising an electrical circuit embodying an oscillation generator, operating means associated with said circuit, including a conductor having a field which when influenced by said object moving therein will vary the tit) resonant frequency of said circuit, said objcct having a different dielectric constant than the medium in which the field occurs, a second electrical oscillation generator connected to said circuit and a sound reproduccr connected to said generators for emitting tones produced by the interference of .the oscillations of said generators.

3. A tone. generating system for producing a plurality of superimposed tones, comprising an electrical oscillating circuit and a control electrode for each tone, the field of said electrode biting controllable by the hand alone when moving therein, means including the control electrodes for varying the resonant frequencies of said circuits in accordance with the tones desired and a reproducer associated with all of said circuits.

4. A tone generating instrument played by hand comln'ising a circuit embodying an oscillation generator, means in said circuit including a conductor external thereto electrically influenced by the movement of the hand for varying the resonant frequency of said circuit at Will, a secondoscillation gel'ierator connected to said circuit to pro-- duce a beat frequency, a detector system coupled with said circuits, a sound reproducer controlled by said detector system and a transformer connected intermediate said reproducer and said detector system.

5. A sound or musical tone generating instrument comprising a circuit embodying an oscillation generator, a second oscillation generator producinga beat frequency there- 'with and means in said circuit including a conductor electrically influenced by body capacitance for varying the resonant frequency of said circuit to produce musical tones at will.

(3. A musical instrument comprising a circuit embodying an oscillation generator, means including an electrode in said circuit for varying the resonant frequency of said circuit at will to produce the desired musical tones, a second oscillation generator connected to said circuit to produce a beat frequency, anamplifier in said circuit, a detector system connected to said amplifier and said second oscillation generator and a sound reproducer connected to be controlled by said detector system.

7. A musical instrument comprising a circuit embodying an oscillation generator, means including an electrode in said circuit for varying the resonant frequency of said circuit at will to produce the desired musical tones, a second oscillation generator connected to said circuit to produce a beat fre quency, an amplifier connected to said second oscillation generator, a detector system connected to said amplifier and the firstmentioned oscillation generator and a sound reproducer controlled by said detector systern.

8. A sound or musical tone generating instrument comprising an electrical oscillating circuit, means including an electrode electrically influenced by movement of the hand for varying the resonant frequency of said oscillating circuit at will to produce the desired musical tones, an electro-ionic tube having a plate and a grid connected to said oscillating circuit to cause an oscillating current to flow therein, said electrode being directly connected to said plate, and a sound reproducer in {said circuit for emitting tones in tUfUtH'dILDCt. with the variations in the oscillations. A

9. A musical tone generating instrument comprising an electrical oscillating circuit, means inchulil'ig an electrode electrically influenced by movement of the hand for varying the resonant frequency of saidoscillating circuit at will to produce the desired musical tones, an electro-ionic tube having a plate and a grid connected to said oscillating circuit to cause an oscillating current to flow therein, said electrode being directly connected to said grid, and a sound reproducer in said circuit.

ll). An instrument for producing musical tones comprising an electrical oscillating circuit, means including an electrode in said circuit for controlling said circuit to produce. the desired tones in accordance with the movement of the hand, two inductances of different values in said circuit, said elec trode being connected to the larger inductance, and a sound reproducer connected with said circuit.

11. A system for generating n'musical tones comprising n+1 circuits, an electrode 7 in each of a plurality of said circuits arranged. to be responsive to manual control and a sound reproducer controlled by the beat frequencies of the currents traversing said circuits.

12. A musical sound generating instrument comprising oscillating circuits, means including a manual control'electrode in each circuit for controlling the frequency of the oscillations therein, a detector system for illitl each circuit, a resultant system to which all said detector systems are connected and asound reproducer controlled by said resultant system.

13. A sound producing instrument comprising oscillating circuits, means including an electrode in each circuit for controlling the frequency of. the oscillations therein at will, oscillating systems to one of which each of said circuits is coupled, each oscillating system comprising a coupling coil, a detector, a coil and a condenser connected in parallel to said last mentioned coil, said coils constituting the primaries of a transformer, a secondary in said transformer, a calibrated circuit, a coupling coil in said calibrated circuit connected to the neutral llld ltd

points of each primary, a generating system to which the secondary of said transformer is connected and a sound reproducer controlled by said generating system.

14. A musical sound producing instrument comprising oscillating circuits, means including an electrode in each circuit for controlling the fre uency of the oscillations therein at will, a de ector connected galvanically to each circuit,.coils connected in series with each detector, condensers connected in parallel to each coil, said coils constituting the primaries of a transformer, a secondary in said transformer, a variable inductance common to all detector circuits a calibrated system com rising a plate and a grid circuit, said inductance being connected to said plate circuit, a generating system to which the secondary of said transformer is connected, and a sound reproducer controlled by said generating system.

15, An instrument for producing musical sound notes comprising oscillating circuits, means including an electrode in each circuit for controlling the frequency of the oscillations therein, at will, a detector connected galvanically to each circuit, coils connected in series with each detector, condensers connected in parallel to each coil, said coils constituting the primaries of a transformer, a secondary in said transformer, a variable inductance common to all detector circuits, a calibrated system comprising a plate and a grid circuit, said inductance being connected to said grid circuit, a generating system to which the secondary of said transformer is connected, and a sound reproducer controlled by said generating system.

16. An apparatus for producing music in imitation of musical instruments comprising an electrical oscillating circuit, means in said circuit including an electrode for controlling the oscillations therein, a sound reproducer in said circuit controlled by the oscillation controlling means, a cathode tube for said reproducer and means including a filament in said tube for regulating the volume of the sound in said reproducer, said last mentioned means also including a volume control electrode connected to the filament.

17. An apparatus for producing sound tones comprising an electrical oscillating circuit, means including an electrode for controlling the resonant frequency of the oscillating circuit, a sound reproducer connected with said circuit and means including a separate electrode for regulating the volume of the sound in said reproducer by varying the electrical field of the electrode.

18. An apparatus for producing sound tones comprising an electrical oscillating circuit, means including an electrode for controlling the resonant frequency of the oscillating circuit, a sound reproducer connected with said circuit, a detector providedwith a filamentary cathode a battery connected with the filament circuit of said detector, a

shunt circuit, and a switch adapted \to close eitltizer the filament circuit or said shunt circui 19. An apparatus for producing musical tones comprising an electrical oscillating circuit, means including an electrode for controlling the resonant frequency of the oscillating circuit, a sound reproducer connected with said circuit, means including a separate electrode for regulating the volume of the sound in said reproducer, a tube associated with said separate electrode, energized by said tube,a detector and an amplifier comprising a filament connected with said detector and controlled by the armature of said relay.

20. An apparatus for producing musical Sound comprising an electrical oscillating circuit, means including an electrode for controlling the resonant frequency of the oscillating circuit, a sound reproducer in said circuit and a second oscillating circuit, the electric oscillation constants of which correspond to the mechanical oscillation constants of said reproducer.

21. Apparatus generative of musical sound comprising an electrical oscillating circuit, means including an electrode for controlling the oscillations therein, a sound reproducer in said circuit, a plurality of electro-ionic tubes of different characteristics connected in parallel to each other and in series with said reproducer and separate resistances for regulating the plate and filament current of each tube.

22. Apparatus generative of musical tones comprising an electrical oscillating circuit. means including an electrode for controlling the oscillations therein, a sound reproducer in said circuit, a detector, a transformer, one winding of which is connected in the plate circuit of said detector and the magnetization of which transformer is regulated by its other winding, a circuit connected with said other winding, a resistance for controlling said circuit and a third winding in said transformer connected with said reproducer.

23. The method of obtaining a definite dependence of the change of the frequency of an oscillating system for producing rela tive changes in pitch of musical tones upon the degree of approach of an object toward a control electrode characterized by the steps of changing the electrical field distribution by varying the relationship of said electrode and said object, and generating sound according to the characteristics of said field.

24. The method of producing musical tones in accordance with the movement of a relay the hand, characterized by generating elec trical oscillations in a circuit, varying the capacitance of a portion of the circuit by movement of the hand in its relation to the circuit, producing from said circuit sounds of variable pitch corresponding to the electrical oscillations and altering the variationsto produce sounds of the ddslred timbre.

25.. In a method of producing musical tones in an electrical continuously oscillating system, the steps of generating oscilla-- tions in the system and which comprises changing the electrical characteristics of said system by movement of a foreign ob- .ject in proximitive relation to a part thereof to vary the electrical capacity of a portion of the system.

26. The method of producing musical tones in an electrical oscillating system em-, hodying two oscillation generators arranged to generate an audible beat frequency characterized by moving the hand in relation to said system in a manner to change the electrical characteristics of one of said generators only, p

27. The methodof producing musical tones which comprises enerating electrical oscillations of ultra-an iblc frequenc generating other oscillations of slight y different frequency, varying the frequency of one series of oscillations by altering the electrical characteristics of the generating system by movin a body in relation to said system and com ining said oscillations to obtain a variable beat-note of audible pitch.

28. The method of producing musicalf tones of controllable pitch, duration and intensity which comprises varyin the constants of the circuit of an electrical oscillator by moving the hand in relation to an element of said circuit, producing from said circuit sound vibrations of variable pitch corresponding to the electrical oscillations and controlling the sound vibrations to vary the duration and intensity of the tones 29. A musical instrument comprising an oscillating system embodying means to be influenced in respect to the frequency of its oscillation by external conditions structural- 1y unrelated thereto, a sound reproducer contill eanna ing systems to produce a beat-note of audible frequency, one of said systems embodying an outwardly projecting conductor and subj'cct to influence in respect of the frequency of its oscillation by external conditions produce a beat-note of audible frequency one of said' oscillatm's having a portion thereof extending outwardly to a position for cooperation with the hand of an operator to vary the oscillations without moving the elements of the last mentioned oscilneither conductively nor mechanically conlater, and a sound reproducer connected to Y said oscillators. v

33. An electrical system generative of musical tones comprising tone-producing means, said means including electrical circuits, a sound reproducer connected to said tone-producing means and means for varying the volume and pitch of the tone emitted by said rcproducer in accordance with the movements of an operators hand in relation to said circuits to generate separate musical notes of the desired duration. r v

34. An apparatus of the class described responsive to a moving external objectcomprising an electrical circuit embodying an.

oscillation generator, means in said circuit including a conductor electrically influenced by the movement of said object for varying the resonant frequency of said circuit according to the movement of the object and 1 means connected to said circuit for emitting tones according to the electrical variations occurring in the circuit. 35. An. apparatus of the class described comprising an electrical oscillator, a sound rcproducer connected to said oscillator, an electrode connected to the oscillator for effecting manual control thereof by variation of the electrical field around theclectrode, means for operating the sound rcproducer in accordance with the variations in the oscillator and means for controlling the volume of the sound from said reproducer.

36. An apparatus of the class described comprising an electrical oscillator. a sound reproducer connected to said oscillator, an electrode connected to the oscillator for effecting manual control thereof by variation of the electrical field around the electrode, and means for operating the sound reproducer to generate musical tones in accordance with the variations in the oscillator including means for controlling the timbre of said tones.

37, An apparatus of the class described comprising an electrical oscillator a sound reproducer connected to said oscillator, an electrode connected to the oscillator for effecting manual control thereof by variation of the electrical field around the electrode, means for operating the sound reproducer in accordance with variations in the oscillator, a second electrode for effecting manual control of the volume of the tones emitted by said reproducer by variation of the electrical field around said electrode and means including said second electrode for controlling the volume of said tones.

38. A tone generating system for producing a plurality ofregisters of superimposed tones, comprising an electrical oscillating circuit and a control electrode for each register, the field of said electrode being con trollable by the hand alone when moving therein, and means including the control electrodes for varying the resonant frequencies of said circuits in accordance with the tones desired.

39. An electrical musical instrument comprising means for controlling the volume of the tones thereof, including an. electrode controlled by body capacitance.

40. In a method of producing musical tones in accordance 'with the movement of the hand, the steps of generating electrical oscillations in a circuit and varying the capacitance of a portion of the circuit by movement of the hand in its relation to the circuit.

In testimony whereof I have signed my name to this specification.

LEO SSERGEJEWITSCH THEREMIN. 

